public void Evaluate(EvalutationContext <ItemRanking> context)
{
if (!(context is ItemRankingEvaluationContext))
{
throw new Exception("Wrong evaluation context.");
}
var model = (IUserItemMapper)context.Model;
var measures = ((ItemRankingEvaluationContext)context).GetTestUsersRankedList()
.Select(url =>
{
var rankedItems = url.GetMappedItemIds(model.ItemsMap);
var correctItems = url.GetMappedCorrectItemIds(model.ItemsMap);
double ap = MML.PrecisionAndRecall.AP(rankedItems, correctItems);
double precAtN = MML.PrecisionAndRecall.PrecisionAt(rankedItems, correctItems, _position);
double recallAtN = MML.PrecisionAndRecall.RecallAt(rankedItems, correctItems, _position);
return(new { AP = ap, PrecAtN = precAtN, RecallAtN = recallAtN });
}).ToList();
if (!context.Items.ContainsKey("AP"))
{
context["AP"] = measures.Select(m => m.AP).Average();
Console.WriteLine(string.Format("AP: {0:0.0000}", context["AP"]));
}
context["PrecAt" + _position] = measures.Select(m => m.PrecAtN).Average();
context["RecallAt" + _position] = measures.Select(m => m.RecallAtN).Average();
Console.WriteLine(string.Format("PrecAt {0}: {1:0.0000}", _position, context["PrecAt" + _position]));
Console.WriteLine(string.Format("RecallAt {0}: {1:0.0000}", _position, context["RecallAt" + _position]));
}
public void Evaluate(EvalutationContext <ItemRating> context)
{
// make sure that the test samples are predicted
context.RunDefaultTrainAndTest();
var testset = context.Dataset.TestSamples;
double sum = 0;
foreach (var itemRating in testset)
{
sum += Math.Abs(itemRating.PredictedRating - itemRating.Rating);
}
context["MAE"] = Math.Sqrt(sum / testset.Count());
Console.WriteLine(string.Format("MAE: {0:0.0000}", context["MAE"]));
}
public void Evaluate(EvalutationContext <ItemRanking> context)
{
if (!(context is ItemRankingEvaluationContext))
{
throw new Exception("Wrong evaluation context.");
}
var model = (IUserItemMapper)context.Model;
double ndcg = ((ItemRankingEvaluationContext)context).GetTestUsersRankedList()
.Select(url => MyMediaLite.Eval.Measures.NDCG.Compute(
url.GetMappedItemIds(model.ItemsMap),
url.GetMappedCorrectItemIds(model.ItemsMap)))
.Average();
context["NDCG"] = ndcg;
Console.WriteLine(string.Format("NDCG: {0:0.0000}", ndcg));
}
public void Evaluate(EvalutationContext <ItemRanking> context)
{
if (!(context is ItemRankingEvaluationContext))
{
throw new Exception("Wrong evaluation context.");
}
var dataset = context.Dataset;
var model = (IPredictor <ItemRanking>)context.Model;
// make sure the model is trained
if (!model.IsTrained)
{
model.Train(dataset.TrainSamples);
}
var mapper = (IUserItemMapper)context.Model;
var testset = dataset.TestSamples.ToPosOnlyFeedback(mapper.UsersMap, mapper.ItemsMap);
var trainset = dataset.TrainSamples.ToPosOnlyFeedback(mapper.UsersMap, mapper.ItemsMap);
var results = _recommender.Evaluate(testset, trainset);
foreach (var item in results)
{
context[item.Key] = item.Value;
Console.WriteLine(string.Format("{0}: {1:0.0000}", item.Key, item.Value));
}
// calculate F1@5 and F1@10
var precAt5 = (float)context["prec@5"];
var precAt10 = (float)context["prec@5"];
var recallAt5 = (float)context["recall@5"];
var recallAt10 = (float)context["recall@10"];
var f1At5 = precAt5 * recallAt5 * 2 / (precAt5 + recallAt5);
var f1At10 = precAt10 * recallAt10 * 2 / (precAt10 + recallAt10);
Console.WriteLine(string.Format("F1@5: {0:0.0000}", f1At5));
Console.WriteLine(string.Format("F1@10: {0:0.0000}", f1At10));
}
public void Evaluate(EvalutationContext <ItemRating> context)
{
if (!(context.Model is IPredictor <ItemRating>))
{
throw new Exception("To predict the full user item matrix the model should implement IPredictor<ItemRating>.");
}
// make sure the dataset is trained
context.RunDefaultTrainAndTest();
Console.WriteLine("Predicting full user-item matrix...");
var recommender = (IPredictor <ItemRating>)context.Model;
var dataset = context.Dataset;
var allItemIds = dataset.AllSamples.Select(ir => ir.Item.Id).ToList();
var allUserIds = dataset.AllSamples.Select(ir => ir.User.Id).ToList();
var writer = new StreamWriter(_outputPath);
// header of the file should be the list of all items
var header = allItemIds.Aggregate("\t", (cur, next) => cur + "\t" + next);
writer.WriteLine(header);
allItemIds.ForEach(u =>
{
string line = u;
allUserIds.ForEach(i =>
{
var itemRating = new ItemRating(u, i);
recommender.Predict(itemRating);
line += string.Format("\t{0:0.00}", itemRating.PredictedRating);
});
writer.WriteLine(line);
writer.Flush();
});
writer.Close();
}
public EvaluationPipeline(EvalutationContext <T> context)
{
Context = context;
Evaluators = new List <IEvaluator <T> >();
}